This invention relates to a oral scavenging hood for use when a nasal anesthesia mask is used for inhaled sedation.
The administration of anesthetic or analgesic (inhalation sedation) gas to patients involves a mask (hood) which is placed over the nose of the patient and the introduction of a controlled amount of gas, through the mask, to the patient. Heretofore, such gas that either has leaked from the mask perimeter or was exhaled by the patient has been allowed to dissipate into the ambient environment. Concerns about the danger presented by this escaping gas in the environment of an operating room, particularly the side effects on personnel who are subject to this environment on a continual basis, have prompted increased attention and approaches to the elimination of such gas escape. Consequently, nasal anesthesia masks including scavenging means are well-known in the art. Among such art, are the following patents:
Kelley U.S. Pat. No. 3,867,936 Patented Feb. 25, 1975
That patent provided a structure whereby while anaesthetic gas which was administered to a patient, and which was exhaled from the patient was passed through a replaceable, man-transportable absorber unit to absorb the anaesthetic gas employed.
Parkes U.S. Pat. No. 4,112,940 Patented Sep. 12, 1978
That patent provided a scavenging valve for anaesthesia gas which was released in pediatric anaesthesia apparatus which was of generally conical configuration and which had an axial bore extending therethrough from an open base to an open apex. A control valve comprised a pair of nipples, each of generally-conical configuration, in base-to-base relation with an axial bore extending therethrough from one open apex end to the other. The control valve had a radially-extending bore which tapered down from the bases. The control valve coupled an anaesthesia bag to the scavenging valve and had a gas flow control and shut off plate pivotally mounted in the bore thereof in the area of the bases of the control valve. A manually-operable control member was provided outside the control valve.
Brown U.S. Pat. No. 4,015,598
That patent disclosed a double wall face mask, i.e., a mask over a mask. The inner mask defined a chamber over the patient's face communicating with a source of gas to be inhaled. The outer mask enclosed and defined an exhaust chamber outside of the inner mask, the exhaust chamber communicating with a gas removal line. A check valve opened the facial chamber to the exhaust chamber during exhalation and the exhaust chamber was open to the surrounding atmosphere adjacent the face-engaging perimeter of the inner mask to draw escaped gases from the surrounding atmosphere into the exhaust passage for disposal.
Czajka U.S. Pat. No. 4,219,020 Patented Aug. 26, 1980
That patent provided a mask assembly for administering a gas to be inhaled by an individual including a mask body to fit over the nose of the individual, and against the surrounding facial area of said individual, the mask body terminating in a peripheral surface contoured to fit against the facial area of said individual and when so positioned defining therewith a mask chamber, the mask body also including an inlet port which was adapted to be operatively connected to a source of gas to be administered to said individual thereby to direct said gas to said mask chamber. Valve means were provided including a valve body member disposed through the mask body in an area of the mask body remote from the contoured peripheral surface, the valve body member including an exhalation valve member movable between a first seated closed position during inhalation of the individual and a second open position during exhalation of said individual, the valve body member including a first exhaust chamber formed about the exhalation valve member to receive exhalation gas of said individual flowing through said exhalation valve member and a second annular exhaust chamber formed of a pair of substantially frustoconically shaped members radiating outwardly from said valve body member and spaced from each other to define said second annular exhaust chamber. Means afforded fluid communication between the first and second exhaust chambers and an outlet port which was adapted to be connected to a vacuum source in one of the exhaust chambers, thereby to provide a source of vacuum to each of the first and second exhaust chambers to exhaust gas exhaled by said individual. The pair of radiating members defined an area at their termini, the area being disposed circumferentially and outwardly of the mask body and being located distantly from the periphery surface and the facial area of the individual when the mask was in use and being spaced from said inlet port. The pair of radiating members had inlet means to the annular exhaust chamber near the outer edge surface of the annular exhaust chamber, thereby to establish a suction effect about the whole exterior of the mask body when the mask body was connected to the vacuum source.
Fischer U.S. Pat. No. 4,248,218 Patented Feb. 3, 1981
That patent provided a scavenging mask apparatus for administering gas to a patient, wherein lost and exhaled gas was scavenged by vacuum means. The apparatus included a nosepiece which was adapted to fit over the patient's nose and was shaped to form a seal between the rim of the nosepiece and the patient's face. Means connected the nosepiece to a source of vacuum. A nasal cannula was disposed inside the nosepiece and attached thereto. Means were provided for connecting the cannula to a source of gas. The constant flow of gas entering the cannula was delivered directly to the patient's nostrils. Any gas escaping from the cannula, as well as gas which was exhaled through the nostrils, was scavenged by the continuous air flow inside the nosepiece and was swept toward the source of vacuum. One or more holes in the underside of the nosepiece broke the vacuum, allowing air flow for scavenging gas exhaled through the patient's mouth. The holes also prevented the mask from locking onto the patient's face due to suction.
Fischer, Jr. et al U.S. Pat. No. 4,25,239 Patented May 5, 1981
That patent provided an exhaust assembly for a gas supply system for administering gas to a patient, the system having a remote vacuum means, a scavenging mask with a peripheral chamber adjacent to the rim of the mask, means for supplying gas to the mask, means for removing exhaled gas from the mask, and an exhaust port communicating with the mask through the means for removing exhaled gas. The exhaust assembly included resistance means communicating with the exhaust port for creating a resistance to gas flow therefrom. It also included divider means for dividing gas flow, the divider means communicating with the resistance means, with the peripheral chamber, with the ambient atmosphere, and with the remote vacuum means, so that the vacuum-induced gas flow was divided between exhaled gas from the exhaust port, scavenged gas from the peripheral chamber and air from the ambient atmosphere.
Thompson, Sr. U.S. Pat. No. 4,312,339 Patented Jan. 26. 1982
That patent provided a system for administering an anaesthetic gas to a patient, including a mask, means for supplying an anaesthetic gas to the mask when the patient inhaled, and an exhaust line having its proximal end connected to the mask and adapted to have its terminal end connected to a source of vacuum to exhaust gas from the mask when the patient exhaled. A closed reservoir was in series with the exhaust line between the proximal and terminal ends thereof. The reservoir had an inlet and an outlet with a check valve adjacent to the inlet to prevent the flow of gas out of the reservoir through the inlet when the patient inhaled. A nozzle was secured to one side of the face mask for scavenging gas escaping from the mask and a second exhaust line was connected the nozzle directly to the upper end of the lower portion of the reservoir. A tube connected the upper and lower portions of the reservoir and had an opening adjacent the bottom of the lower portion of the reservoir.
Hoenig U.S. Pat. No. 4,527,558 Patented Jul. 9, 1985
That patent provided a gas scavenger system which included a collection manifold that collected the waste gases as they left the normal exhaust ports of the demand valve. A flexible tubing means then carried those collected gases to a surge chamber prior to eventual discharge into a vacuum system. The surge chamber provided an interface between the vacuum system and the collection manifold and was connected to the vacuum system through a predetermined sized orifice which limited the flow to the vacuum system to a maximum known flow. The surge chamber normally allowed continuous flow through the orifice to the vacuum system but was sized to accumulate an excess of flow from the collection manifold under abnormal conditions, such as was occasioned when a patient coughed, to allow time to remove the gases through the orifice and thus to prevent leakage to atmosphere.
Schmoegner et al U.S. Pat. No. 4,770,169 Patented Sep. 13, 1988
That patent provided an anaesthetic mask comprising a wall forming a respiratory chamber having a rim sized and configured generally to conform to a selected area surrounding the nose and/or mouth of a patient, the rim having a closed-loop perimeter and a generally "Y"-shaped cross section. An anaesthetic gas inlet was mechanically associated with the respiratory chamber for connection to an anaesthetic gas supply. An exhaust outlet was mechanically associated with the respiratory chamber for connection with a vacuum supply. A face seal was connected to the rim, the seal including, a closed-loop seal body defining a vacuum channel therein and further including a plurality of openings arranged to provide gas intercommunication between the vacuum channel and the exterior of the seal body, the seal body enclosing said rim. Vacuum connection means was included for providing gas intercommunication between the vacuum channel and the vacuum supply.
Olsson et al. U.S. Pat. No. 4,905,685 Patented Mar. 1990
That patent provided equipment for administering gaseous anaesthetic to a patient which had at least one anaesthetic reservoir serving as the originating source for anaesthetic and a ventilator to which the gas is supplied from the reservoir, the ventilator being in communication with the breathing passages of a patient. The exhalation gas from the patient was fed back to the originating anaesthetic source via at least one filter in which predetermined gas components were filtered out. The exhalation gas could then be returned to the originating source either directly or through a compressor.
Werner et al. U.S. Pat. No. 5,044,361 Patented Sep. 3, 1991
That patent provided a method and an apparatus for reuse of anesthetics in inhalation anaesthesia is described. The apparatus included a collector conduit to be connected to a patient and an anesthetics evaporator which is connected to the collector conduit via an outlet. An adsorption filter containing an adsorption material for adsorption and desorption of anaesthetic gas in gaseous form was arranged in the collector conduit distally relative to the outlet from the anesthetics evaporator, thereby leading the exhalation gas through the adsorption filter in a first direction and the inhalation gas through the adsorption filter in a second direction which was opposite to the first direction.
Burkhart U.S. Pat. No. 5,044,363 Patented Sep. 3, 1991
That patent provided an apparatus for scavenging an anaesthetic substance from a waste gas flow leaving an anaesthetic-administration system. The waste gas flow included at least a flow of unused anaesthetic in gas or vapour form and anaesthetic in the exhalation from a patient. The apparatus included means for containing a quantity of a replaceable adsorbing medium, which was disposed to receive a flow of waste gas from the anaesthetic-administration system to percolate the waste gas through the adsorbing medium for adsorption of the anaesthetic substance by the adsorbing medium. The apparatus also included means for quickly connecting and disconnecting the containing means to the anaesthetic-administration system in such a manner that the waste gas flow was caused solely by an internal pressure within the anaesthetic administration system.
Psaros et al U.S. Pat. No. 5,471,979 Patented Dec. 5, 1995
That patent provided apparatus which included means for connection to a patient via a connector for ventilating the patient with an anaesthetic gas and respiration gas, the patient thereby producing exhaled gas, in an exhalation line, containing anaesthetic gas which was not absorbed by the patient and carbon dioxide, and a remainder of exhaled gas. An adsorption filter communicated with the exhalation line for directing the exhaled gas through the adsorption filter for adsorbing the anaesthetic gas in the exhaled gas which was not adsorbed during respiration, and thereby simultaneously unavoidably adsorbing a small amount of carbon dioxide and for permitting the remainder of exhaled gas to pass through said adsorption filter means. Means were provided for evacuating the remainder of exhaled gas. An inhalation line, was provided which was separate from the exhalation line. Carbon dioxide absorber means were disposed in the inhalation line between the adsorption filter means and the connector. Means were provided for directing fresh respiration gas which had passed through the adsorption filter means through the carbon dioxide absorber for absorbing the small amount of carbon dioxide. A bypass line bypassed the adsorption filter and the carbon dioxide absorber. Means were provided for directing fresh respiration or fresh anaesthetic gas from the means for ventilating through the bypass line. Finally, means were provided for combining the gas directed through the bypass line with the fresh gas which had passed through the adsorption filter means and the carbon dioxide absorber in a desired gas concentration for forming a mixture and for supplying the mixture to the connector.
Landis et al U.S. Pat. No. 5,657,752 Patented Aug. 19, 1997
That patent provided a positive nasal airway pressure mask, including means for securing the mask to the patient's head, i.e., a head strap or harness, a primary air tube to be connected to a source of air pressure in a known manner, and a nasal mask to deliver pressurized air to the nose of the patient. The nasal mask included one or more variable orifice members with the nasal mask. The variable orifice member or members responded to increased air pressure within the mask at various stages of operation, e.g., exhalation, to relieve excess pressure.